Flood Risk and Vulnerability Analysis Project - Atlantic Climate ...

steady increases in both summer and winter. This represents an influence towards increased
flood risk across the Province, especially in winter for all WRMD regions. Winter thaws and rain
events could lead to increases in rain on snow flooding. Winter rains also lead to greater risk of
rain on frozen ground events where the ground‟s ability to absorb liquid is compromised.
On average, Newfoundland and Labrador is affected, or threatened, by one or two tropical
storm systems each year, based on 21 tropical storms tracking across or near Newfoundland
and Labrador from 1954 – 2011.
Climate change currently being experienced across much of the globe, including Newfoundland
and Labrador, will continue to promote an increase in the frequency of tropical cyclone
development over the Tropical Atlantic through the end of the 21st century. Additionally, storms
are expected to mature into more intense hurricanes (higher category) and are expected to
have an increased ability to survive their track towards Atlantic Canada, arriving with more force
as the increasing water temperatures south of Newfoundland will not provide as much
resistance to promote weakening as experienced before the 1990‟s.
Hurricanes, with their combination of abundant rains over wide areas and strong winds
producing significant storm surge and waves, have, like Hurricane Igor, caused some of the
worst and costliest floods in Newfoundland. With increased frequencies and intensities
anticipated in the coming decades, flooding events of the magnitude of Hurricane Igor, a
Category 1 storm, are likely to occur more frequently. As Atlantic sea surface temperatures
warm, the probability of another Category 2 hurricane making landfall in Newfoundland
increases. In addition, it would not be unrealistic to expect a first Category 3 hurricane to make
landfall in Newfoundland before 2080, perhaps before 2050.
Sea level is an ocean indicator for climate change. Sea level in the Province has been
observed to be rising relative to benchmarks and wharf deck elevations. The rate of global
mean sea level rise is presently estimated at about 3 mm/year, yet another confirmation that
global warming is already underway. There are regional differences also. For the North
Atlantic, a comparable rate of about 2.5 mm/year is estimated. These rates may increase with
continued melting of the polar ice caps and warming of the oceans.
Sea level also changes locally in relation to the geological uplift or subsidence of the earth
which is in response to the retreat of the ice sheets that covered and depressed the land during
the last glaciation, some 10,000 to 20,000 years ago. Though uplift has slowed since the glacial
sheet melted, it is still occurring at different rates over the Province. Geophysical modelling
indicates uplift rates of 0 to 4 mm/year for Labrador and the Northern Peninsula, and
subsidence rates of 0 to 2 mm/year for Newfoundland. The net long term sea level effect is the
sum of global sea level changes and local geological impact.
The two major currents that influence the local weather and global climate of Newfoundland are
the Labrador Current and the Gulf Stream. The Labrador Current carries cold and relatively
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